Power supply

ABSTRACT

In a television receiver employing vacuum tubes, and which includes a fullwave bridge rectifier circuit for developing the required direct operating potential for the circuits, and for energizing the filaments, an instant-on circuit delivers one-half wave rectified voltage to the filaments of the vacuum tubes during standby operation by opening the circuit in one leg of the bridge rectifier using one section of a standby switch. The circuit delivers fullwave rectified voltage to the filaments during normal operation. A second section of the standby switch disconnects the bridge rectifier from the power supply filter during standby operation thereby preventing the application of the operating potential to the circuits during the standby operating mode.

actuator 40c. thereby breaking the magnetic contact with the head 420 ofactuator 40c and allowing the spring 44:: to return the the latter tothe open circuit position, thereby turning off the lights, and leavingthe lighting circuit open even when the door Me is again closed.

FIG. diagrammatically illustrates another embodiment of the inventionwherein the automobile lights may be operated in conventional manner,with the present improvement being separately operable to bypass thelight switch 60d and operate the automobile lights independently whenswitch 60d is in "off" podtion.

Referring more particularly to FIG. 10, it will be noted that there is adoor operated circuit breaker or switch d, having an actuator button86dcorresponding in use to slide button 36 of FIG. 2, or pushbutton 86of FIG. 7. The operation of actuator button 86d, closes the lightcircuit as described in connection with the combinations illustrated inFIGS. 2, 7 and 9, so that opening of the door 14d adjacent the driverwill automatically open the light circuit and turn off the lights. Wherea solenoid is used as previously described, wires 47d and 48d are usedto supply electric current for the operation of same when pushbutton 86dis depressed.

Although certain preferred embodiments of the invention have beendisclosed, it will be readily appreciated that other equivalentstructures can be utilized to obtain the same results. For example, themagnet 52 need not be a permanent magnet but can be an electromagnet.Furthermore, the latching mechanism 50 need not be a magnet at all, butcould instead be a mechanical catch or the like which engages the head42 when fully extended and the door closed, but which breaks away fromthe head when the door is opened, and it is intended that the showing inthe drawings be considered to diagrammatically illustrate the alternateelements described in this paragraph. Consequently, the preferredembodiments disclosed herein are not to be regarded as showing the onlypossible forms of the invention, but instead as illustrating theconcepts underlying it.

I therefore particularly point out and distinctly claim as my invention:

1. In combination with a motor vehicle having a door and an electricalsystem including a battery, at least one headlight, and a light switchconnected in a circuit including said battery and said headlight, anautomatic headlight turnoff system comprising: a switch having terminalmeans connected into the headlight circuit to open and close the sameand having a movable actuator means; means for mounting said actuatormeans generally adjacent said door and movable with respect thereto;means for effectively latching said actuator means against said doorwhen the latter is in a closed position; means for biasing said actuatormeans away from its said latched position when said door is opened; andmeans for moving said actuator means toward its said latched positionagainst said biasing means.

2. The tumoff system as defined in claim 1, wherein said switch includesa housing portion and said actuator means includes a member extendingoutwardly of said housing.

3. The. tumofi system as defined in claim 1, wherein said latching meansincludes a magnet and said actuator means carries a ferromagneticportion to latch by magnetic attraction to said magnet.

4. The turnoff system as defined in claim 3, including means formounting said magnet on said door.

5. The turnoff system as defined in claim 3, wherein said means formoving said actuator means includes a slide and a manually actuablehandle member.

6. The turnoff system as defined in claim 5, wherein said switchincludes a movable contact carried by said slide and positioned to closea circuit across said terminal means only when said actuator means islatched by said latching means.

7. The turnoff system as defined in claim 1, wherein said means formoving said actuator means includes a solenoid.

8. The turnoff system as defined in claim 7, wherein said actuator meanscomprises an armature for said solenoid.

9. The turnoff system as defined in claim 7, including a manuallyactuable electrical switch for energizing said solenoid and means forbiasing said switch normally in the open circuit position.

10. The turnoff system as defined in claim I, wherein said turnoffsystem includes a first movable member (50:) mounted for movement towardand away from said door. means for biasing the movement of such member,and a second movable member (40c), and wherein said latching means (520)holds said members in a predetennined mutual position in which the firstmember contacts said door.

11. The turnofi system as defined in claim 10, wherein said latchingmeans includes a magnet.

12. The turnoff system as defined in claim I 1, wherein said magnet iscarried by one of said movable members.

13. The tumofi system as defined in claim 10, wherein one of saidmovable members carries a movable contact comprising a part of saidswitch.

POWER SUPPLY This invention relates to power supplies for televisionreceivers. v

In recent years, vacuum tube television receivers have employedinstant-on circuits which apply reduced power to the vacuum tubefilaments during a standby mode of operation. The warmup time of theinstrument is thus greatly reduced when switched into operation. Thereduced power during standby operation has been accomplished for exampleby placinga diode across the power switch. When in the standby operationhas been accomplished for example by placing a diode across the powerswitch. When in the standby condition (power switch open) one-half waverectified voltage is applied to the filaments. When in operation (powerswitch closed) the diode is electrically shorted and an alternatingcurrent delivers full power to the filaments. Other systems utilize thepower supply rectifier diode and a double pole switch to couple thediode to the filament string during standby operation whilesimultaneously disconnecting the diode from the direct power outputcircuit. During operation, the diode is switched into the direct voltagepower output circuit and the filament string is coupled to analtematingvoltage. Common to both of these methods and other similar systems isthe application of onehalf wave rectified voltage to the filamentsduring standby operation and an alternating voltage (not rectified) tothe filaments during normal operation. The circuitry of the presentinvention, however, supplies full-wave rectified direct voltage to thefilaments during normal operation, and half-wave rectified voltage tothe filaments during standby operation.

Operation of the filaments by full-wave rectified voltage isadvantageous in that raster movement due to leakage of alternating powerline frequency current between the filaments and cathodes of stages suchas the horizontal oscillator is prevented. This movement can beparticularly objectionable where the frequency of input power to thereceiver varies considerably from the television field transmissionrate, for example, when the power line frequency is 50 Hz. and thetelevision field rate is 60 Hz. I

Due to the reduced cost of solid state diodes, it is economicallyfeasible to employ full-wave bridge rectifiers as the means forsupplying the direct operating potential (8+) in receivers. A costadvantage is realized since the B+ filter may employ aresistance-capacitance (R.C.) type filter rather than theinductance-capacitance (L.C.) filter usually necessary when onlyhalf-wave rectification is used. A preferred embodiment of the presentinvention combines an instant-on feature which provides full-waverectified direct current to the filaments during operation with afull-wave rectifier power supply circuit in an economical system whichreduces the raster movement problem.

A circuit embodying the present invention includes means for producing afull-wave rectified voltage which is coupled to the filament string ofthe vacuum tube television receiver, and to the direct operating voltagecircuit Switching means are provided to convert the full-wave rectifiedvoltage coupled to the filaments during normal operation to half-waverectified voltage during a standby mode of operation.

FIG. 1 is a block diagram of a television receiver of the type includingvacuum tubes which are illustrated diagrammatically in several of thestages.

FIG. 2 is a schematic circuit diagram showing the direct voltage supplyused to power the receiver shown in FIG. 1. The diagram includes thefilament string for the vacuum tubes of FIG. 1 and the instant-onfeature of the present invention.

FIG. 3 is a schematic diagram illustrating an alternative embodiment ofthe present invention which can be substituted'in the circuit shown inFIG. 2. I

Referring now to the television receiver of FIG. I, an antennareceives-composite television signals including audio, video, andsynchronizing signals and couples .these signals to the tuner 20. Thetuner 20 includes a radiofrequency amplifier with a vacuum tube 22having a filament 21 and local oscillator and mixer stages whichincorporate a dual purpose vacuum tube 24 having a filament 23. Thetuner 20 amplifies the incoming composite signals and converts thesesignals to lower intermediate frequency (I.I-.) signals which are thencoupled to the LP. section 25 of the television receiver. l.F. stage 25includes two amplifier stages having vacuum tubes 26 and 28 withfilaments 27 and 29 respectively. The LP. stage 25 amplifies thefrequency converted composite signals and couples them to the video andautomatic gain control (A.G.C.) stage 30 of the receiver which includesa vacuum tube 32 having a filament 31 and which is of the dual purposetype. The

' triode section of vacuum tube 32"is'utilized in a conventional ized asvideo output amplifier, andarnplified video signals therefrom arecoupled to a control element 34 of a kinescope 35 having a filament 33.

Amplifier stage 40 is coupled to the video amplifier 30 to receivesynchronization and audio signals. Included in stage 40 is a dualpurpose vacuum tube 42 having a filament 41. The pentode section of tube42 is utilized as an audio I.F. amplifier, and the amplified audio I.F.signals are coupled ,to the audio detector and output stage 45. A duelpurpose pentode tube 48 having a filament 47 detects the audiofrequencycomponents of the audio I.F. signal, amplifies the resulting audiosignals; and couples them to a speaker 49 to reproduce the audio portionof the television program.

The synchronizing signals coupled to stage 40 are amplified by thetriode amplifier and are coupled to sync. separator stage 50 whichseparates the horizontal and vertical sync. components and couples themto the horizontal oscillator stage 55, and to the vertical oscillatorstage -65 respectively. The horizontal oscillator includes a vacuum tube58 having a filament '57. Horizontal frequency 15,734 Hz. signalsdeveloped by the oscillator are coupled to the'horizontal output stage60 which includes a horizontal output tube 62 having a filament 61 and adamper diode 64 having a filament 63. The horizontal outputstage 60provides the horizontal deflection current by meansof interconnectionX--X, to a horizontal yoke 36 associatedwith the kinescope 35. Likewisethe vertical oscillator and output stage 65 provides the verticaldeflection current by means of interconnection Y Y, to a vertical yoke38 also associated with the kinescope 35. Having described the receiverwhich includes several vacuum tube stages and which is, typical of manyreceiver types, attention is directed to FIG. 2.

In FIG. 2 there is illustrated the power supply for providing the directoperating potential (8+) to the various stages of. the receiver of FIG.I, also shown is the series filament string which is supplied withoperating power in the unique manner to be described.

In the figure, line. voltage is supplied to power transformer 75 bymeans of a power switch 70. This switch will normally be in the closedposition since the instant-on feature is utilized to activate anddeactivate the receiver. The transformer 75 has a bridge rectifiercircuit comprising diodes 71, 72, 73, and 74 coupled across itssecondary winding. A switch section a comprising one pole of adouble-pole single-throw switch 80 is shown coupled in series with diode74. Switch 800 could, however, be coupled in series with any of thediodes 71, 72, 73, or 74. An output terminal A is coupled by means of asecond switch section 80b comprising the other pole of switch 80 to theB-loutput terminal via a-diode 91 and a filter network includingcapacitors 92 and 94 and a resistor 93. Terminal A is further coupled tothe series string of filaments by means of a voltage droppingresistor81. The numerals associated with the filaments shown in FIG. 2correspond to the numerals accompanying the filaments in the vacuumtubes-of FIG. 1. Several filter components including capacitors 82, 83,85, 86, 87, 89, and a resistor .84; and an inductor 88 are included asshown in the filament string to provide the'desired filtering to eachtube during operation.

In operation, the circuit provides power to the receiver in thefollowing manner. With the switch 70 closed transformer 75 providesalternating voltage AC to the bridge circuit including diodes 71, 72,73, and 74. When the receiver is in the on" condition, i.e., beingoperated, switch 80 will also be closed thus ganged switch sections 800and 80b will be in the closed position. The bridge operates in aconventional manner to produce a full-wave rectified voltage waveform atoutput terminal A. The full-wave rectified current is coupled by meansof closed switch section 80b of switch 80 to the B+ filter and providesthe operating direct current DC power to the receiver. Diode 91 conductsthe charge the input filter capacitor 92 while also preventing theaccumulated charge on this capacitor from leaking back through thefilament string thereby lowering the B+ output voltage. Full-waverectified current from terminal A is coupled to the series filamentstring to power the vacuum tube filaments. For standby operation switch80 is opened and switch section 80b disconnects the B+ filter fromtenninal A thereby turning off the operating DC power to the receiver.Simultaneously, switch section 80a is opened and the bridge rectifierdevelops one-half wave rectified direct current to terminal A as diodes72 and 73 conduct. In this mode of operation the conduction pathincluding diode 71, transformer 75 secondary and diode 74 is broken andonly one-half wave rectified voltage will appear at terminal A. Theaverage power delivered to the filaments is therefore reduced toapproximately one-half which is sufficicnt to maintain them in thedesired standby condition. Although switch section 800 of switch 80 isillustrated serially coupled to diode 74 it is easily seen that thecircuit operates equally well with the switch serially coupled to any ofthe diodes in the bridge rectifier. It is noted that transformer 75 willprovide isolation to the receiver chassis which from the AC line can beoperated as a cold chassis? an advantage when a metal cabinet is beingused to house the receiver. The invention, however, has equalapplicability to receivers which operate directly off the powerlinewithout incorporating a power transformer such as transformer 75 shownin FIG. 2.

FIG. 3 illustrates an alternative embodiment of the present inventionwherein a center tapped transformer 100 and two diodes 102 and 104replace the bridge circuit of FIG. 2. Point A of FIG. 3 is coupled tothe same point as terminal A in FIG. 2. Switch 105 is the same as switch80 pole 80a in FIG. 2. In operation, switch 105 is closed and full-waverectified voltage appears at terminal A. In the standby mode switch 105is opened thereby reducing by one-half the power supplied to thefilaments via terminal A. It is seen that switch 105 can be placed inseries with either of diodes 102 or 104.

The following circuit parameters were utilized in the preferredembodiment shown in FIG. 2.

Transformer 75 approximately l:l

turns ratio Diodes 71,72,73.74.91 IN 4004 Resistors 81 27 ohms 84 6.8ohms 93 62 ohms Capacitors 82 L000 picofarads 83 1,000 picofarads 851,000 picofarads 86 0.01 microfurads 87 1.000 picofarads 89 1,000picofarads 90 1,000 picofarads 92 250 microfarads 94 400 microfuradsVacuum Tubes 1. A power supply for electronic apparatus including atleast one vacuum tube with a filament comprising:

means for providing source of alternating voltage, rectifying meanscoupled to said source of alternating volt- 2 age to develop therefrom afull-wave rectified voltage between a pair of output terminals, meansfor connecting said vacuum tube filament between said output terminals,and switching means coupled in circuit with said rectifying 2 means forconverting the voltage developed between said output terminals tohalf-wave rectified voltage during a standby mode of operation.

2. A circuit is defined in claim 1 wherein said supply means comprises atransformer having a primary winding adapted to be coupled to a sourceof alternating voltage and a secondary winding for developingalternating voltages of opposite polarities at opposite ends of saidsecondary winding.

3. A circuit is defined in claim 2 wherein said transformer includes agrounded center tap secondary winding.

4. A circuit is defined in claim 3 wherein said rectifying meanscomprises at least two diodes, each coupled to one of said opposite endsof said secondary winding and to said output terminal to provide afull-wave rectified voltage at said output terminal, and

said switching means comprises a switch serially coupled with one ofsaid diodes.

5. A circuit is defined in claim 1 wherein said rectifying meanscomprises a full-wave bridge having a diode in each leg of said bridgeand said switching means comprises a switch coupled in series with adiode in any one leg of said bridge.

6. A power supply comprising:

a full-wave bridge rectifier circuit having input and output terminalsand at least one rectifier in each leg of said circuit, said inputterminals being adapted to be coupled to a source of alternatingvoltage,

means for coupling said output terminals to at least one vacuum tubefilament to provide power thereto, and

switching means coupled in series with one rectifier contained in saidbridge rectifie; for providing a full-wave rectified voltage at saidoutput terminal when said switching means is in a first state and ahalf-wave rectifier voltage at said output terminal when said switchingmeans is in a second state.

7. A circuit as defined in claim 6 wherein said switching means presentsa closed circuit in said first state and an open circuit in said secondstate.

8. A circuit as defined in claim 6 and further including:

further switching means operable in synchronism with said switchingmeans for coupling said output terminal to a 6 direct current powersupply filter circuit when said switching means is in said first state.

1. A power supply for electronic apparatus including at least one vacuumtube with a filament comprising: means for providing source ofalternating voltage, rectifying means coupled to said source ofalternating voltage to develop therefrom a full-wave rectified voltagebetween a pair of output terminals, means for connecting said vacuumtube filament between said output terminals, and switching means coupledin circuit with said rectifying means for converting the voltagedeveloped between said output terminals to half-wave rectified voltageduring a standby mode of operation.
 2. A circuit is defined in claim 1wherein said supply means comprises a transformer having a primarywinding adapted to be coupled to a source of alternating voltage and asecondary winding for developing alternating voltages of oppositepolarities at opposite ends of said secondary winding.
 3. A circuit isdefined in claim 2 wherein said transformer includes a grounded centertap secondary winding.
 4. A circuit is defined in claim 3 wherein saidrectifying means comprises at least two diodes, each coupled to one ofsaid opposite ends of said secondary winding and to said output terminalto provide a full-wave rectified voltage at said output terminal, andsaid switching means comprises a switch serially coupled with one ofsaid diodes.
 5. A circuit is defined in claim 1 wherein said rectifyingmeans comprises a full-wave bridge having a diode in each leg of saidbridge and said switching means comprises a switch coupled in serieswith a diode in any one leg of said bridge.
 6. A power supplycomprising: a full-wave bridge rectifier circuit having input and outputterminals and at least one rectifier in each leg of said circuit, saidinput terminals being adapted to be coupled to a source of alternatingvoltage, means for coupling said output terminals to at least one vacuumtube filament to provide power thereto, and switching means coupled inseries with one rectifier contained in said bridge rectifier forproviding a full-wave rectified voltage at said output terminal whensaid switching means is in a first state and a half-wave rectifiervoltage at said output terminal when said switching means is in a secondstate.
 7. A circuit as defined in claim 6 wherein said switching meanspresents a closed circuit in said first state and an open circuit insaid second state.
 8. A circuit as defined in claim 6 and furtherincluding: further switching means operable in synchronism with saidswitching means for coupling said output terminal to a direct currentpower supply filter circuit when said switching means is in said firststate.